Installers can fit solar panels on tiled, slate, metal and flat roofs, or on purpose-built ground structures. However, the right mounting system depends on the roof covering, supporting structure and roof condition. The design must also account for wind, snow, waterproofing and the panel layout.
Quick answer: there is no universal mounting system for every roof. Instead, a safe installation needs a certified system that suits the building. Site-specific structural and wind-loading calculations must support the design.
What does a solar mounting system do?
The mounting system transfers panel weight and wind and snow forces into the building structure or ground. It must keep the panels secure throughout the installation’s design life. At the same time, it must preserve the roof covering, drainage, fire performance and weather-tightness.
The current MCS Solar PV Installation Standard, MIS 3002:2025 requires structural and wind-loading calculations for the chosen mounting system. Therefore, a parts list alone cannot replace a design for the specific project.
Solar panel mounting systems at a glance
| Roof or site | Common mounting approach | Main design checks |
|---|---|---|
| Tiled pitched roof | Roof-specific brackets, rails and module clamps | Tile profile, supporting structure, weathering and fixing positions |
| Slate roof | Slate-compatible brackets or flashing systems | Slate condition, fixing detail, water path and fragile materials |
| In-roof solar | Integrated trays and flashings replace part of the roof covering | Module compatibility, roof pitch, ventilation and full weathering detail |
| Trapezoidal metal roof | Profile-specific short rails or rail systems | Sheet thickness, purlins, pull-out resistance, sealing and corrosion compatibility |
| Standing-seam roof | Approved seam clamps, often without roof penetration | Seam type, clamp approval, roof warranty and load transfer |
| Flat roof | Ballasted or mechanically fixed low-angle frames | Structure, membrane, drainage, wind zones, ballast and fire/access routes |
| Ground mounting | Piles, ground screws, concrete foundations or engineered ballast | Ground conditions, planning, wind/snow load, drainage and cable route |
Mounting solar panels on tiled pitched roofs
On-roof mounting is common on pitched domestic roofs. First, roof-specific support brackets connect the rails to suitable structural members. Installers then align the aluminium rails and secure the panels with clamps approved for the module frame.
The exact fixing method depends on the tile, roof construction and certified mounting system. Installers must avoid placing structural loads or damaging pressure on the tiles. To keep the roof weather-tight, they must follow the complete approved fixing and roof-covering detail. Generic sealant around a bracket cannot replace this detail.
On-roof systems normally allow airflow behind the panels, which helps remove heat. They are also relatively straightforward to inspect, remove or replace when the roof needs maintenance.
Solar panel mounting on Scottish slate roofs
Natural slate roofs are common across Edinburgh, East Lothian and central Scotland. Although slate is durable, it can be brittle, particularly on an older roof. The installer must therefore assess both the covering and supporting structure before fitting panels.
A slate installation needs brackets and a weathering method that suit the roof construction. Installers may need to carefully remove and refit slates around fixing positions. They then use purpose-made flashings or replacement details to maintain the water path. They should also check for hidden defects, nail sickness, cracked slates and access for future maintenance.
If your slate roof is nearing the end of its service life, consider repairs or reroofing before fitting solar panels. This can avoid the later cost of removing and reinstalling the array.
On-roof or integrated in-roof solar?
On-roof panels
These panels sit above the existing tiles or slates. This is often the most practical option for a sound existing roof because the original roof covering remains in place and air can circulate behind the modules.
Integrated in-roof panels
In contrast, in-roof systems replace part of the normal roof covering. The panels sit within certified trays and flashings that form part of the weathering layer. This flush finish can suit new builds, extensions and reroofing projects. It also removes the open gap beneath a conventional on-roof array.
Integrated systems need careful design around roof pitch, panel dimensions, battens, ventilation, flashings and drainage. Higher panel temperatures can affect output. However, designers should assess this using the chosen product’s current performance data rather than a universal percentage penalty.
Mounting solar panels on metal roofs
Trapezoidal and corrugated sheet roofs
Commercial units, agricultural buildings and outbuildings often use profiled metal sheets. Compatible short rails or full rail systems can provide an efficient installation. However, the fixing specification must account for the exact profile, sheet material and thickness. Designers must also check purlin positions, fastener pull-out resistance and wind loading.
Installers may use manufacturer-approved fasteners and sealing washers where the certified design allows roof penetration. However, rubber backing alone does not make a fixing waterproof. The installer must follow the complete tested detail and ensure compatibility with the roof material and warranty.
Standing-seam metal roofs
Standing-seam roofs can often accept purpose-made clamps that grip an approved seam without penetrating the roof sheet. However, the seam profile, sheet manufacturer, clamp type and load calculations must all be compatible. Because not every clamp suits every seam, the installer must check compatibility and the roof warranty before work begins.
Fibre-cement roofs and asbestos
Older commercial and agricultural roofs may contain asbestos cement. Do not drill, cut or disturb the material until the appropriate asbestos-management process establishes its composition and condition. If that process confirms asbestos, seek specialist advice. Roof replacement may also be necessary before solar installation.
Flat-roof solar mounting systems
Installers normally fit flat-roof arrays at a low angle using ballast or engineered mechanical connections. First, the design team must check structural capacity, local wind pressure and membrane compatibility. They must also assess drainage, fire performance, access routes and how loads act on the roof.
Ballasted systems
A ballasted system uses calculated weights to resist movement and wind uplift without routinely penetrating the roof membrane. Protective layers also distribute loads and separate the frame from the membrane. The mounting manufacturer’s design software calculates the ballast requirements. It uses building dimensions, height, location, roof-edge zones, panel layout and local wind and snow conditions.
Never choose ballast using a generic rule of thumb. Too little creates a movement risk, while too much can overload the roof structure.
Mechanically fixed systems
Where ballast is unsuitable, installers may connect a frame to engineered roof anchors or structural supports. The team must design and complete roof penetrations and membrane connections using an approved weathering detail. This normally requires coordination with the roofing manufacturer or warranty provider.
East–west or south-facing mounting on a flat roof?
East–west arrays place panels back-to-back at a low angle. They can make efficient use of roof space, reduce the gaps required between rows and spread generation more evenly between morning and afternoon. The compact aerodynamic arrangement can also reduce ballast requirements in some engineered systems.
South-facing rows may produce more energy per panel over a year where shading and tilt are favourable. However, they generally need wider row spacing to avoid shading each other. The best option depends on available area, electricity demand, shading, structural capacity and the mounting-system calculation. An east–west layout does not automatically generate 30% more energy.
Read our detailed guide to south-facing and east–west solar panels.
Ground-mounted solar panels
A ground-mounted array can be useful when the roof is unsuitable or when available land allows a larger system. Residential and commercial structures may use driven piles, ground screws, concrete foundations or engineered ballasted frames.
The design must consider ground conditions, slope, drainage, wind and snow loads, and shading. It must also allow for maintenance access, fencing or livestock, vegetation and the underground cable route to the electrical equipment. In addition, planning permission is more likely to be relevant than for a modest domestic roof array.
What we check before selecting a mounting system
- roof covering, pitch, age and remaining service life
- rafter, truss, purlin or deck construction
- existing damage, movement, leaks or corrosion
- roof membrane type and warranty conditions
- possible asbestos-containing materials
- site-specific wind and snow exposure
- panel dimensions, clamp zones and array layout
- shading, orientation and expected generation
- roof drainage, edge zones and maintenance access
- fire performance and required access routes
- planning, building standards and listed-building constraints
Renew-Able Solutions carries out detailed site surveys for domestic solar PV and commercial solar installations. These can include a 3D drone survey and internal LiDAR scan where appropriate, helping us inspect the roof geometry, supporting structure, equipment locations and cable routes before final design.
Structural and wind-loading calculations
Designers should check the panel layout and mounting components for the actual installation address and building. For example, wind pressure can be much higher around roof edges and corners. Exposed coastal or elevated Scottish sites may therefore need different fixing spacings, rail layouts or ballast from a sheltered low-rise property.
The structure must also support the permanent weight of the panels and mounting equipment. Temporary snow loads and concentrated ballast loads need checks too. If information is missing or the team identifies concerns, further structural assessment may be necessary before installation.
Will solar panel mounting cause roof leaks?
A correctly designed and installed mounting system should preserve the roof’s weather-tightness. However, unsuitable brackets, damaged tiles or slates, and poorly positioned fixings can cause problems. Roof penetrations without an approved detail and existing roof defects also increase the risk.
First, the surveyor should record the roof condition before work begins. Installers should then follow the mounting-system and roofing manufacturers’ instructions. They should also replace cracked or defective covering materials where necessary.
Do solar panels need planning permission in Scotland?
Many domestic roof-mounted solar installations fall within permitted development rights in Scotland, but conditions apply. Listed buildings, properties within the curtilage of a listed building, World Heritage Sites and prominent elevations in conservation areas can require additional consent. Ground-mounted and non-domestic arrays have their own limits.
The current Scottish Government solar-panel guidance sets out the householder rules. If the property’s status or proposed layout creates uncertainty, consult the local planning authority.
Frequently asked questions
Can solar panels be installed on any roof?
Not always. The roof needs suitable condition, structure, shape and access, as well as a compatible mounting system. Some roofs may therefore need repairs, strengthening or reroofing first.
Are solar panels too heavy for an older roof?
Age alone does not decide this. Instead, the assessment must consider the structure, roof covering, existing condition and calculated loads. An older roof may be suitable, while a newer lightweight structure may need further checks or strengthening.
Is an east–west flat-roof layout better?
It can be better where roof space is tight or electricity use continues throughout the day. However, a south-facing layout may produce more energy per panel. We compare annual yield, usable roof area, shading, ballast and consumption before deciding.
Can solar panels be fitted to a listed building?
Possibly, but you may need listed-building consent and planning permission. Discuss the visual impact, roof fabric and setting with the local planning authority.
Should I replace my roof before installing solar?
If you expect major repairs or reroofing during the solar installation’s life, consider completing them first. This is normally cheaper than paying to remove and reinstall the panels later.
Arrange a solar roof survey
Renew-Able Solutions designs roof- and ground-mounted solar PV systems for homes and businesses across Edinburgh, East Lothian and wider Central and East Scotland.
Contact us to arrange a solar survey, or learn about our solar PV inspection and servicing.
